The present invention relates to high speed flywheels, particular to a means containing fragments of flywheels undergoing structural failure, and more particularly to a lightweight flywheel containment structure composed of a plurality of layers of different materials.
High speed flywheels are being developed for a variety of applications, and such flywheels typically have rotational speeds of 20,000 to 100,000 rpm. Structural failure of a flywheel rotating at such speed cause damage to surrounding equipment due to the fragments being thrown from the rotating flywheel. Such fragments may have sufficient mass and speed so as to present a lethal hazard to persons in the area. Rim speeds of the rotors range from 500 to 1,200 m/s. The typical high speed flywheels are composed of high strength carbon fiber composites, and thus structural failure of such flywheels rotating at high speeds produces high speed fragments, which has been a major concern in this developing technology.
Prior efforts have been directed to the development of containment structures for flywheels, which include containment housings in which the flywheels rotate, and heavy containment structures which surround the flywheel. However, heavy containment structures surrounding the flywheel increase the weight of the flywheel assembly and thus decreases the efficiency thereof. Such high weight containment structures reduce the benefit of the power peaking capability of flywheels for mobile applications, for example, such as hybrid vehicles, automobiles, trucks, buses, and trains. Thus, there has been a need for a means by which structural flywheel failure can be contained without the need of encasements or containments which prevent power peaking.
The present invention provides a solution to the above-referenced problems relating to high speed flywheels, by providing a structure encasing or surrounding the flywheel which is capable of containing fragments due to flywheel failure, while using materials having a structural weight that is not excessive and thus does not reduce the benefit of the power peaking capability of flywheels. The lightweight flywheel containment of the present invention utilizes of plurality of layers of different material which act as a vacuum barrier, momentum spreader, energy absorbers, and reaction plate. The lightweight flywheel containment can be utilized on high speed flywheels having stationary applications as well as mobile applications for power peaking.
It is an object of the present invention to absorb the energy of a flywheel structural failure.
A further object of the invention is to contain high speed fragments resulting from flywheel structural failure.
A further object of the invention is to provide a lightweight flywheel containment.
Another object of the invention is to provide a lightweight flywheel containment encasing the flywheel and composed of a plurality of layers of various materials.
Another object of the invention is to provide a lightweight flywheel containment which includes an inner high toughness structural layer, an energy absorbing layer, and an outer support layer, which may be positioned around the flywheel rotor, or optionally spaced from the rotor through a layer impedance matching material.
Another object of the invention is to provide a lightweight flywheel containment structure composed of a combination of materials in various layers of material which act as a vacuum barrier, momentum spreader, energy absorber, and reaction plate.
Other objects and advantages of the present invention will become apparent from the following description and accompanying drawings. The invention is directed to a lightweight flywheel containment for high speed flywheels capable of operating in the 20,000 to 100,000 rpm range. The flywheel containment is composed of a combination of materials arranged in such a way as to absorb the energy of a flywheel failure. The flywheel containment includes various layers of material which act as a vacuum barrier, momentum spreader, energy absorber, and reaction plate. Due to the structural arrangement and the lightweight of the flywheel containment, it can be utilized in stationary applications and in mobile applications for power peaking. An embodiment of the flywheel containment is composed of an inner high toughness structural layer, an energy absorbing layer, and an outer support layer, with the inner layer being encased about the flywheel rotor or spaced from the rotor by a layer of impedance matching material. The lightweight containment structure can be utilized with flywheel rotors operating at rim speeds of 500-1,200 m/s, and the tests have shown that the containment structure is capable of containing fragments resulting from high speed structural failure.